A problem is created when different people desire to view different TV programs, or to listen to audio in different languages. In a home environment this situation typically results in different members of the family watching different TVs in different rooms of the home. For a number of reasons this common solution to the problem is less than desirable. For example, this solution to the problem requires the family to own multiple TVs, and possibly multiple reception devices, such as cable converter boxes and/or satellite antennas. This problem is compounded if one of the TVs is a large screen TV, which may be in demand by all of the family members.
In the field of stereo computer graphics it is known to project different images for the left and right eyes. A viewer then uses so-called shutter glasses to view the image in stereo. The shutter glass system works by closing the shutter for one eye for a brief period during which the other eye views what is displayed on the screen. This process is alternated for the left eye and the right eye. The images on the screen are adapted for each eye, based on the displacement between the viewer's eyes. So when the shutter for the left eye is open, it displays the image for the left eye and vice-versa. The persistence of human vision ensures that the images are "seen" simultaneously. The use of such a system enables a viewer to view a displayed image in a stereoscopic sense, and thus perceive depth.
In greater detail, in such traditional stereo graphics displays a receiver on the shutter glasses, such as an infrared (IR) receiver, receives a synchronization signal from the stereo monitor. The synchronization signal causes liquid crystal (LC) panels or shutters in the glasses (one for each eye) to switch from being opaque to transparent and vice versa. When opaque, the viewer cannot see through the shutter. The shutter for the left and right eye switch in an alternate fashion and, at any given time, only one eye can see the displayed image. However, the persistence of human vision results in both eyes seeing their corresponding images simultaneously.
While the LC shutters are being controlled in this fashion, the display monitor is displaying images alternately for the left eye and right eye. The image for the left eye differs from the image for the right eye. This difference is what gives the perception of depth. In a computer generated image, the image for the left eye is created by treating the center of the camera to coincide with the center of the left eye and vice-versa. As a result, the two images differ in camera position.
Some stereo and virtual reality systems use small displays (e.g., LCDs) provided within head sets worn by a user. However, the use of such a system presents at least two problems. The first is the current low resolution of such displays, resulting in poor image quality. The second, and more important problem, is that the use of the head set isolates the viewer from his or her surroundings, making it difficult for the viewer to interact with objects and persons in the viewer's environment.
At present, there is no system known to the inventor that allows viewers to simultaneously watch different programs using the same TV monitor.